A typical tapered roller bearing may include a bearing cone having an inner bearing race, a plurality of rollers within a roller cage, and an outer bearing race. Typically, a pair of tapered roller bearings, may be mounted on a wheel axle for rotation of the wheel. An adjustable ring or spacer such as that disclosed in commonly owned U.S. Pat. No. 3,774,896 and commonly owned U.S. Pat. No. 4,125,929, each invented by the inventor herein, may be placed between the bearings. Such a spacer contains a compressible area which may comprise a curved section. The adjustable spacer is mounted between two opposed bearings on an axle or spindle to allow a load to be applied on the bearings while maintaining the bearings in a desired axial position. When the bearings are forced towards each other with a predetermined load, the spacer will axially compress.
Typically the area of load distribution of the adjustable spacer is a relatively narrow annular surface which contacts the inner race. Usually the radius of the corner between the side wall of the inner race contacting the spacer and the inner diameter of the inner race contacting the axle or spindle is small enough so that the spacer side wall contacts the flat portion of the side wall of the inner race. If the radial height of the spacer (the difference between the outer diameter of the spacer and inner diameter of the spacer measured from its imaginary central axis) is large enough to contact the flat portion of the side wall of the inner race, proper load distribution through the inner races and spacer may be obtained. In most cases, the contact area between the spacer and inner race side walls is relatively large enough to evenly distribute the force of contact therebetween.
In some case, however, the aforementioned corner radius of the inner race is large relative to the narrow annular surface of contact on the spacer. In such a situation, the distribution of force through contact between the spacer and inner race may occur within the corner radius (curved portion of the inner race near the axle or spindle). When the force of contact through the spacer is applied at the corner radius, the spacer can become wedged between the inner race and the shaft, causing unpredictable increases in the compression force necessary to properly adjust the bearing setting. Additional force may then be needed to adjust the load on the bearing therefore defeating the purpose of providing a constant compression force spacer.
The aforementioned problem could be alleviated by increasing the contact region of the spacer. However, an increase in the contact region is limited by the limits of tool extensions that can be used efficiently to machine the internal groove surface or compressible area of the spacer. The longer the tool required for such machining, the more susceptible it is to breaking by the chip loads of machining. Standard grooving tools, particularly of the type known as tungsten carbide insert tools, are usually only able to machine grooves about 0.100" (2.5 mm) deep. However, since corner radii of bearings are often 50% to 100% larger than this, a solution must be found.
In addition to the aforementioned problem, wheel axle or spindle assemblies may also have a variable diameter. For example, a smaller diameter portion may be located at the end of the axle with a larger diameter portion located at or near the opposite end. A conical portion of the axle may function as a transitional area between the large and small diameter portions. A bearing assembly configuration commonly found in such wheel axle assemblies includes two bearings of different diameters each mounted on the different diameters of the axle. In such a bearing/axle assembly, there may be little or no room for an adjustable spacer adjacent to the smaller diameter bearing. Also, the adjustable spacer may not be capable of being mounted directly between each of the opposed spacers.
Therefore, a need exists for an adjustable spacer which may be used in situations where the radius of curvature between the side wall and inner diameter of the inner race is relatively large compared to the area of contact between the inner race and the adjustable spacer. A need also exists for an adjustable spacer, and/or assembly therefor, which may be used with bearings of different diameters mounted on an axle or spindle having different diameters.